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VI. USING THE PSEUDO DISK

Once the pseudo—disk has been initialized and installed(by

running the appropriate BASIC program or BRUNing the SATURN DISK

program), it can be used as a standard disk drive. Its directory

will be empty and files can be saved on it like a real disk

drive. The number of files that can be stored on the pseudo—disk

is limited to the amount of memory being used for it. (Saturn 32K

boards, 64K, 128K and 16K cards)

Due to the unique organization of the PSEUDO—DISK (32

sectors/track), standard track and nibble copy programs cannot

generally be used to copy data to or from it. In fact, FID must

be modified to enable it to transfer files properly from a real

disk drive (16 sectors) to the pseudo disk (32 sectors). This

modification is accomplished by running the program, MOD, pro-

vided on the distribution diskette included with the Saturn 64K

and 128K RAM boards.

MOD will modify FID so that it can be used with the PSEUDO—

DISK, as well as with the relocated DOS (see Chapter 4). The

modified FID can be used as a direct replacement for FID (as

distributed on the DOS 3.3 system master), with or without a

PSEUDO—DISK or the relocated DOS.

The data will remain on the pseudo—disk as long as power is

applied, or until the data is deleted. The data is still present

even after a re—boot on the system.

VII. HOW IT WORKS

The PSEUDO DISK system consists of the following programs:

1. PSEUDO DISK— This is an Applesoft program which provides

the interface between the user and the machine language

programs (PSEUDO.NRM, PSEUDO.MVD) that do the actual

patching of DOS and installation of the driver routines

for the PSEUDO DISK, for emulation of a disk drive. The

program generates a binary data file PSEUDO PARAMETERS

which contains information regarding the location and

types of RAM boards in the system as well as the slot

and drive specified for the PSEUDO DISK. This file is

updated whenever the PSEUDO DISK is set—up (option 2 of

the main menu.

2. PSEUDO.NRM— This program does the actual installation of

the PSEUDO DISK and initialization of the system

(including the directory, if desired). The driver

routines for the PSEUDO DISK are located between the

file butters and start of DOS, with HIMEM being adjusted

downward.

3. PSEUDO.MVD— This program does the actual installation

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